A method of controlling a relative movement of a cutting blade and a workpiece which are moved relative to each other by a movement device in an operation with a machine tool. The method includes a step of bringing the cutting blade and an object into contact with each other, by moving at least one of the cutting blade and the object toward each other by the movement device, and a step of controlling the relative movement on the basis of a relative position of the cutting blade and the object which is detected by the movement device upon the contact of the cutting blade and the object with each other. The method further includes a checking step of checking if a contact detecting device for detecting the contact of the cutting blade and the object is in a normal condition in which the contact detecting device is capable of detecting the contact when the cutting blade and the object are brought into contact with each other; and a contact determining step of determining that the cutting blade and the object have been brought into contact with each other, in accordance with an output provided by the contact detecting device.